Physiological condition and migratory experience affect fitness‐related outcomes in adult female sockeye salmon

Relating fish physiology, behaviour and experience to fitness‐related outcomes at the individual scale is ecologically significant, but presents difficulties for free‐ranging fishes in natural systems. Physiological state (e.g. level of stress or maturity) and experience (e.g. habitat use or exposure to stressors) may alter the probability of survival or reproduction. This study examined the relative influence of physiology and migratory experience on survival, migration duration, reproductive longevity, and egg retention in adult female sockeye salmon (Oncorhynchus nerka) from a Fraser River population. One hundred and thirty‐five females were plasma sampled and tagged with radio transmitters and archival temperature loggers. Fish were tracked 55 km through two natal lakes to spawning grounds, following passage of a hydroelectric dam. For 39 females, we assessed the proportion of time within an optimal temperature (T_optAS) window (13.4–19.5°C), which provides ≥90% of maximum aerobic scope. Females with lower plasma glucose concentrations were more likely to reach spawning grounds. Early migrants spent longer in natal lakes. More time in the T_optAS window was associated with greater reproductive longevity and lower probability of egg retention. Later arriving females had reduced longevity on spawning grounds, as did females that retained eggs. Exposure to higher dam discharge was associated with reduced reproductive longevity and greater probability of egg retention, but not lower survival, indicating a delayed effect of dam passage. Our results underscore the complexity of factors governing fitness‐related outcomes for salmonids, particularly the importance of female experience in the days and weeks prior to spawning.     

50年来金沙江干流水温变化特征分析

基于金沙江干流巴塘、石鼓、华弹3个水文站的50年来水温监测数据,利用线性回归和小波分析的方法,探讨了金沙江干流的水温变化特征,辨识了气候变化和水电工程对水温变化的影响。金沙江干流水温沿程逐渐递增,并呈现出多时间尺度的周期性变化,除年变化外,还存在4～6年、10～12年的变化周期。气候变化对金沙江水温的影响主要体现在年均水温的变化：近50年来,3个测站的年均水温逐渐增加,变化率约0.0063～0.0170℃/年。支流水电开发对华弹站水温的影响主要体现在年内的水温变化,升温期水温比建坝前有所降低,4月份降幅最大,达0.8℃;降温期水温比建坝前有所升高,12月份升幅最大,达1.8℃。     

基于SPSS的重力坝变形监测资料多元逐步回归分析

通过对某混凝土重力坝垂直位移观测数据的回归分析,验证SPSS软件在大坝安全监测数据分析中的可应用性。利用SPSS软件的多元线性回归分析功能自动完成回归分析模型的回归参数计算、回归方程的统计检验和预报方差分析,确定出大坝垂直位移的影响因子为温度、水位及时效,总结出不同影响因子对位移的影响规律。     

土石坝应力应变计算方法概述

概述土石坝应力应变计算方法的发展过程,详细介绍国内外比较经典的计算方法和模型(有限单元法、邓肯双曲线模型、修正剑桥模型、南水模型))的特性、使用范围以及不足之处,为土石坝的设计、稳定分析、渗流计算、抗震分析提供参考。     

基于故障树的土石坝安全警情指标体系结构

大坝警情指标是用来描述大坝安全预警系统研究对象的。警情指标体系的合理性、完整性、可测性和无冗余性,直接关系系统的安全可靠性。在分析影响土石坝安全因素的基础上,合理确定土石坝安全因素集,并基于故障树分析理论建立土石坝警情指标体系结构。     

基于突变分级模型的淤地坝坝系规划方案优选

淤地坝坝系规划方案优选需要考虑水沙控制能力、拦泥能力、淤地能力与投资效益等多方面的因素,是一个典型的复杂系统多准则决策问题,复杂系统多准则决策通常具有模糊性与不确定性.利用突变理论处理模糊与不确定问题的优势,提出了淤地坝坝系规划方案评价指标体系,建立了基于突变分级评价法的淤地坝坝系规划方案优选模型,给出了应用该模型的具体步骤.将该模型应用于偃师市浏涧河流域坝系方案优选中,对底层指标量纲一化处理并进行归一运算,利用归一公式的聚集机理对各指标的重要性进行量化,比较各方案的总突变隶属函数值,从而确定淤地坝坝系规划方案优选结果.结果表明:方案Ⅰ,Ⅱ,Ⅲ总突变隶属函数值分别为0.959 2,0.918 1,0.948 4,方案Ⅰ最优,其评价结果与传统的人工对比分析方法评价结果一致,从而验证了突变分级评价模型用于淤地坝坝系规划方案优选的合理性和可行性.     

丁坝坝面及背水坡水毁与防护模型试验研究

针对丁坝坝面及背水坡水毁问题,采用物理模拟方法,进行正态水槽概化模型试验研究。通过试验,分析丁坝坝面及背水坡的水毁过程,找到破坏的关键点。在此基础上,分析丁坝坝面及背水坡水毁机理,根据相应部位水流特点及破坏形式设计出混凝土浆砌条石护面和混凝土块铰链排护面2种整治防护结构,并对2种结构进行比选。试验结果表明:丁坝坝面及背水坡水毁的主要动力是高速翻坝水流,破坏程度与丁坝前后的跌水高度有关,混凝土块铰链排护面结构具有较好的防护性能。     

新疆生产建设兵团农一师四座平原水库渗透稳定研究

渗透破坏是平原区水库大坝发生破坏的主要形式,渗透稳定问题是平原区水库存在的主要问题。在南疆平原区水库除险加同地质勘察过程中,发现水库坝体（基）实际所承受的水力比降远未达到理论计算的允许比降,水库大坝就已发生了渗透破坏,本文以兵团农一师新井子水库、多浪水库、上游水库、胜利水库为列,分坝体、坝体（基）结合处、坝基等不同部位进行研究,提出较合理的临界比降计算方法。     

山西白猪高产仔母系体重性状的遗传力估计

为了解山西白猪高产仔母系的遗传特性,利用WOMBAT软件,采用平均信息约束最大似然法(AIREML),估计了山西白猪高产仔母系不同阶段体重性状的遗传力。结果表明,初生重遗传力较低,为0.090,断奶重、70日龄体重和180日龄体重的遗传力分别为0.147、0.302和0.157,属于中等遗传力。体重性状受母体效应的影响比较大,母体效应估计值在0.140~0.618之间,且生长早期受母体效应的影响比生长后期大。     

Regularity of the saturation lines’ change and stability analysis oftailings dam in the condition of flood

Yangtianqing tailings dam is a new dam planned for a copper mine. At the design period, test in laboratory is carried out to simulate the process of dam pile based on the design information of Yangtianqing tailings dam. And the regularity of the saturation lines’ change at the condition of flood and normal is studied, when the dam have been heaped to the about 2/3 of the total height (120 m). Based on the test data, the stability coefficients of the dam at this height in different conditions are obtained with the Slide software, and they could be served for the following test and the mine’s future safety production. It is shown that the dam is safe in the normal condition, while in the condition of flood, the stability coefficient is less than the benchmark in national standard. Thus, it is necessary to rectify the preliminary design or to take other measures to ensure the safety of the tailings dam.